Method and composition for ink jet printing on a nonabsorbent substrate

ABSTRACT

Ink jet printing on a non-absorbent substrate involves a wet primer having a primer viscosity. The wet primer is applied on the non-absorbent substrate. An ink jet ink having an ink jet viscosity lower than the primer viscosity is jetted over the wet primer while the primer is still wet. The wet primer and ink are simultaneously cured on the substrate.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 12/398,900, filed Mar. 5, 2009 now U.S. Pat. No. 8,133,539,which is hereby incorporated herein in its entirety.

U.S. patent application Ser. No. 12/398,900 claims benefit of U.S.provisional patent application Ser. No. 61/034,382, filed Mar. 6, 2008,which is also incorporated herein in its entirety by this referencethereto.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates to ink jet printing. More particularly, theinvention relates to preparing inkjet substrates.

2. Discussion of the Background Art

Modern ink jet printing techniques are useful for printing on a varietyof substrates. Ink jet printing allows application of ink to discretelocations by jetting drops of ink on the substrate. Ink jet printingefficiently provides a high degree of printing control with almosteffortless and endless color control and selection. The combination ofthese attributes makes ink jet printing an attractive substitute fortraditional impact processes, such as lithograph and flexographicprinting, which have been used in the past.

The differences in interaction of the ink and the substrate that occurwith ink jet printing may not allow for a simple and direct transitionfrom a traditional printing techniques, such as flexography orlithograph techniques, to an ink jet process, particularly with regardto printing on non-absorbent substrates. A direct transition usingcurrent methods results in inferior ink lay, poor print quality, andexcessive mobility of the ink jet ink that can cause such defects ascratering or pinholing. Attempts to adapt ink jet methods withoutsacrificing ink lay and print quality have led to the production ofvarious basecoat formulas or ink chemistry modifications which onlymarginally improve the final product. Current modifications of ink jetprinting techniques are inadequate because of a lack of parameters thatinsure appropriate ink jet application. Additionally, currentmodifications of ink jet printing techniques fail to mask any surfacefeatures on an underlying substrate, thereby amplifying the appearanceof pinholes, craters, and other surface defects.

Accordingly, there is a need for improved ink jet printing methods anddetailed parameters to optimize the ink jet printing methods with avariety of substrates.

SUMMARY OF THE INVENTION

An embodiment of the invention provides techniques for ink jet printingon a nonabsorbent substrate. One embodiment of the invention comprisesapplying a wet primer having a primer viscosity onto the non-absorbentsubstrate; ink jet printing an ink jet ink having an ink jet viscositylower than the primer viscosity over the wet primer while the primer isstill wet; and simultaneously curing the wet primer and ink on thesubstrate. In various embodiments, techniques of immobilizing an ink jetink on a non-absorbent substrate comprise applying an even layer of aprimer by a flexographic process onto the non-absorbent substrate;jetting the ink over the even primer layer while the primer is stillwet; maintaining the system at a constant temperature above 20 degreesC.; and simultaneously curing the wet primer and the ink on thesubstrate. Inventive techniques include those of ink jet printing onto ametallic substrate that comprises applying a primer having a primerviscosity of from about 100 to about 300 centipoises onto the metallicsubstrate, such that the primer coated surface has a surface energy offrom about 20 to about 50 milliNewtons per meter; and inkjet printing anink having an ink viscosity lower than the primer viscosity over theprimer while the primer is wet, where the primer is present in a densityof about 2 to about 6 g/m² of film as formed by the primer.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

In various embodiments, the invention enables ink jet ink to be printedon a non-absorbent substrate. The non-absorbent substrate is coated witha wet primer having a primer viscosity. An ink jet ink having an ink jetviscosity lower than the primer viscosity is jetted over the wet primerwhile the primer is still wet. The wet primer and inkjet ink coatedsurface are then cured.

Non-absorbent substrates for use in connection with the inventioninclude substrates that are not capable of drawing in or absorbing theprimer or ink into the substrate. Exemplary non-absorbent substrates caninclude, but are not limited to, metals, plastics, glass, and mirrors,for example. The non-absorbent substrates can have a roughened surface,whereby the primer or ink settles into a crater or pit on the surfacebut is still not be absorbed into the substrate. Non-absorbentsubstrates can also include substrates that traditionally have a higherporosity than those listed above, but that have otherwise been treatedto reduce their porosity significantly, such as a paper substrate coatedwith a non-absorbent barrier layer.

In embodiments where the substrate is metallic, the metallic substratecan be selected from metals, metal alloys, and metal-containingsubstrates, such as metallized paper, metallized paper board, andmetal/plastic composites. In various embodiments, the metal substratecan be made of, e.g. tin, aluminum, and/or stainless steel. The metalsubstrate, or any other substrate, can be cleaned to remove surfacecontamination from dirt, dust, oil, and the like as part of the surfacepreparation to provide a non-contaminated surface on which to apply theprimer and the ink jet ink. These surface contaminants are common tometallic substrates and, if left untreated, can cause imperfections onthe printed substrate.

In various embodiments, the metallic substrate can be provided in asheet form that can be shaped after printing into a formed product.Exemplary formed products include, e.g. metal cans, signage, decorativelabels or decals, and various automotive or computer components.

The primer or undercoat composition is deposited as a layer on asubstrate by any suitable method that can apply a continuous layer tocover and wet the underlying substrate. A wet layer provides a liquidinterface onto which the ink jet ink is printed and secured. The primercan be applied by such techniques as, e.g. roll coating, the use of adoctor blade, jetting, or by a flexographic technique. The primer layeris preferably even and has substantially the same thickness across thesubstrate. Preferably, there is less than a 5% variance in the thicknessof the primer as measured across the substrate. Applying the even layerof primer, when combined with the primer characteristics detailed laterherein, provides a simple and effective technique for inkjet printing onnon-absorbent substrates.

The primer viscosity is preferably sufficiently high to prevent mobilityof the primer with respect to the non-absorbent substrate and to makethe primer soluble in the ink jet ink. In various embodiments, theprimer can have a viscosity of from about 100 to about 300 centipoises,a viscosity of from about 200 to about 300 centipoises, or a viscosityof from about 140 to about 150 centipoises. The primer can be applied ata temperature of from about 20° C. to about 40° C., or at a temperatureof 35° C. The viscosity of the primer may be controlled during theprocess. In various embodiments, the process is conducted such that theviscosity of the primer does not significantly decrease through theprinting process. For example, the temperature may be controlled so asto not decrease primer viscosity by maintaining a temperature at orabove the application temperature during the ink printing process.Accordingly, in such embodiments, the primer remains at the same orincreased viscosity from the point of dispensing until after the finalcuring of the printed substrate.

The applied primer layer has a thickness sufficient to provide a smoothsubstrate. In various embodiments, the primer layer has a thickness offrom about 1 to about 50 μm. For example, the primer may be applied inan amount sufficient to provide a film having a film weight of about 2to 6 g/m² over the substrate.

Suitable primer compositions include curable overcoat varnishes wellknown in the industry, such as compositions containing curable epoxyresins. An exemplary, suitable primer composition is the coater varnishsold as ICIMAR™ MD UV 2020RS by ICI Packaging Coatings Ltd. of SuttonFields, England. The primer compositions useful herein can be cured by acationically-driven process or by a radically-driven process. In variousembodiments, the primer compositions include cycloaliphatic epoxideresins or modified cycloaliphatic epoxide resins.

The primer composition used to form the primer coating layer can besubstantially colorless or can include one or more colorants, such asdyes, pigments, and mixtures thereof. In various embodiments, the primeris clear and is preferably non-yellowing, particularly when exposed toactinic radiation during cure. In various other embodiments, the primercan have a light color. The light color can be useful, for example, overa dark colored substrate, such as certain metallic substrates. A whiteprimer can be obtained, for example, by using titanium dioxide dispersedwith a suitable dispersant in a UV Matrix. The number and kinds of anyadditional colorants depends upon the primer being formulated. Theprimer composition can comprise from about 2% to about 40% of colorantby weight of the composition.

For the primer composition to spread well on the substrate, the liquidstate of the composition preferably has a relatively low surface energyor low surface tension, as compared to the substrate surface. A lowsurface energy, radiation curable fluid that is useful as the primercomposition can be obtained by adding suitable low surface energymonomers. Examples of such monomers include, without limitation,isodecyl acrylate, with a surface tension of about 28.6 dynes/cm;alkoxylated nonylphenol acrylate, with a surface tension of about 28.5dynes/cm; and propoxylated neopentyl glycol diacrylate, with arelatively low surface tension for a diacrylate of 32 dynes/cm. Theprimer can have a surface energy of from about 20 to about 50milliNewtons per meter. In various embodiments, the primer can have asurface energy of about 20 to 25 milliNewtons per meter.

The primer compositions of the invention can also include suitableadditives that enhance the wetting of the substrate, includingsurfactants, plasticizers, diluents, wetting agents, and leveling agentsknown to those skilled in the art. Examples include crosslinkablesilicone acrylates, such as Tegorad 2100; a polydimethyl siloxane, suchas Byk-333; or a leveling additive, such as Byk-381, available fromByk-Chemie.

After application of the primer, an ink jet ink is jetted onto the layerof primer. The ink jet ink solvates the primer. The primer partiallyimmobilizes the ink jet drops on the substrate to facilitate adherenceof the ink jet drops on the substrate. Further, the solvation of theprimer by the ink prevents excessive mobility of the drops andcoalescence of the drops near each other. The selective immobilizationcontains a drop in a specific area, generally the area upon which thedrop was deposited. The selective immobilization allows the drop tospread from the deposition point but without distorting the image. Theselective immobilization prevents run-off or ink defects that occur whenusing known ink jet printing techniques on non-absorbent surfaces.

The ink jet viscosity is preferably from about 5 to about 100centipoises. The ink may be jetted at a temperature of from about 20° C.to about 70° C.

Typical ink jet ink formulations include monofunctional andpolyfunctional monomers of acrylate and low viscosity vinyl materials.Examples of suitable monofunctional monomers include, withoutlimitation, alkylenediol diacrylates, such as 1,6-hexanediol diacrylateand neopentylglycol diacrylate; cyclohexanedimethanol diacrylate,polyalkylene glycol di(meth)acrylates, such as triethylene glycoldiacrylate; ether modified monomers, such as propoxylatedneopentylglycol diacrylate; and higher functionality monomers, such astrimethylolpropane triacrylate, trimethylolethane triacrylate, andpentaerythritol tetracrylate, and so on, as well as combinations of suchpolyfunctional monomers. The polyfunctional monomers can includepolyacrylates.

The ink also can include a reactive oligomer. Examples of suitablereactive oligomers include oligomers comprising an ethylenicallyunsaturated double bond, such as acrylated epoxy oligomers, acrylatedpolyurethane oligomers, acrylated polyester oligomers, and combinationsof these. In various embodiments, reactive oligomers comprise more thanone ethylenically unsaturated double bond.

In various embodiments, the ink can be formulated to provide flexibilityand elasticity of the ink on the printed substrate. The increasedflexibility and elasticity of the ink prevents cracking when theink-coated substrate is formed, then placed in a water bath. In variousembodiments, the ink can be formulated to provide a sufficient glasstransition temperature and tensile strength of the cured ink film toallow the printed substrate to withstand a water bath temperature ofless than 55° C. without exhibiting the cracking phenomenon. Forexample, the flexibility and elasticity can be provided by incorporatingparticular monomeric or oligomeric units in the ink formulation orthrough incorporation of chain transfer agents in the ink.

Suitable flexibility and elasticity enhancing monomeric units include,e.g. isobornyl acrylate (IBOA), sold by Sartomer Company, Inc. of ExtonPa., USA; stearyl acrylate; urethane acrylates; and polyester acrylates.In ink formulation embodiments containing isobornyl acrylate, theisobornyl acrylate component can comprise from about 25% to about 55% byweight of the ink formulation. In still further embodiments, theisobornyl acrylate component can comprise at least about 30% to 40% byweight of the ink formulation. Suitable diacrylates that can provideflexibility and elasticity include, e.g. propoxylated neopentyl glycoldiacrylate, marketed as SR9003 by Sartomer Company, Inc. of Exton, Pa.,USA. In various embodiments, the diacrylate can be present in theformulation at from about 10% to about 60% by weight. Other suitablemonomeric or oligomeric materials include the low-viscosity acrylatemonomer CD420 sold by Sartomer Company, Inc. of Exton, Pa., USA. The lowviscosity monomer can be present in the ink formulation at from about 0%to about 20% by weight. In ink formulation embodiments containingisobornyl acrylate, the isobornyl acrylate component can comprise fromabout 25% to about 50% by weight of the ink formulation. In stillfurther embodiments, the isobornyl acrylate component can comprise atleast about 30% to 40% by weight of the ink formulation. Exemplaryformulations for the flexible and elastic inks are provided in theExamples herein.

The flexibility and elasticity of the ink can also be enhanced whenshorter monomeric units or lower molecular weight chains are employedthrough the chain transfer agent. Various mercaptans are useful as chaintransfer agents in embodiments of the invention and prevent the crackingphenomenon of the inks when the inks are subjected to the water bath.

The pigment or pigments in the ink jet ink can be any of those suitablefor ink jet inks. In general, pigments for ink jet inks have a maximumparticle size that is small enough to avoid clogging the ink jets duringprinting. The pigments preferably have a narrow particle sizedistribution. Among these are C.I. Pigment Yellow 93, 95, 109, 110, 120,128, 138, 139, 151, 154, 155, 173, 180, 185 and 193; C.I. Pigment Orange34, 36, 43, 61, 63 and 71; C.I. Pigment Red 122, 202, 254, and a solidsolution of C.I. Pigment Red 122 and 202; C.I. Pigment Blue 15:3 and15:4; C.I. Pigment Violet 19, 23 and 33; and C.I. Pigment Black 7. Theink jet inks are preferably used in a set that provides for full-colorprinting of images. In one preferred embodiment, an ink set includingcyan, magenta, yellow, and black (CMYK) inks is used. For example,yellow, C.I. Pigment Yellow 138, 151, 154, 180, and 185 can be used inthe yellow ink; C.I. Pigment Red 122 and 202, 254, and C.I. PigmentViolet 19 can be used in the magenta ink; C.I. Pigment Blue 15 can beused in the cyan ink; and an acidic or neutral pigment of C.I. PigmentBlack 7 can be used in the black ink.

The amount of pigment included in the ink depends upon, for example,which pigment is used. In general, the ink jet ink contains from about0.5 to about 30% by weight of pigment. While a sufficient amount ofpigment is included to attain the desired color density of the ink,including more pigment also tends to increase viscosity. Suitablepigments are available, for example and without limitation, fromClariant Corporation of Coventry, R.I. and Ciba Specialty ChemicalsCorp. of Basel, Switzerland. In some embodiments, other ink jet inkadditives can be added, including, but not limited to up toapproximately 10% solvent.

The ink jet ink is printed over the primer coating. The ink jet ink canbe printed using drop-on-demand (DOD) inkjet printer. The ink jet inkcan printed in particular using piezo-driven DOD heads (modules) wherethe ink is ejected in accordance with a digitally driven image byflexing of a piezoelectric crystal in the print head. The printingmodule typically has a large number of nozzles, and the printer is madeup of an aligned group of modules. An example of a piezo-driven printingmodule is the SL-128 print head from Spectra that jets a nominal 80picoliter drop.

After the ink is printed onto the primed substrate, the primer and theink jet ink are simultaneously cured and hardened by exposure to actinicradiation, thermal energy, or both actinic radiation and thermal energy.Actinic radiation includes electromagnetic radiation, such as visiblelight, UV radiation or X-rays, and corpuscular radiation, such aselectron beams.

If cured by UV light, the primer and ink jet ink compositions typicallycomprise at least one photoinitiator, or photoinitiator package. Ifpresent, the photoinitiator package typically comprises from about 2 toabout 20% of the total binder, i.e. reactive materials, by weight.Non-limiting examples of photoinitiators include alphahydroxy ketones,such as 1-hydroxy-cyclohexyl-phenyl-ketone; alpha aminoketones, such as2-benzyl-2-(ditnethylamino)-1-(4-morpholinyl)phenyl)-1-butanone; acylphosphines, such as Diphenyl(2,4,6-tritnethylbenzoyl)phosphine oxide;benzophenone derivatives; thioxanthones, such as isopropylthioxanthone(ITX); and amine coinitiators, such as ethyl-p-dimethyl amino benzoate.If cured by e-beam technology, no photoinitiator package is required foran acrylate based ink or primer.

A cationically cured ink can contain epoxide-functional vinyl ethers,such as triethylene glycol divinylether and/or aliphatic epoxies, suchas the cycloaliphatic epoxide UVR-6105, commercially available from DowChemical in Midland, Mich.; a colorant and additives, as describedabove; and a photoinitiator package that contains arylsulfonium salts,such as Cyracure UVI-6992, or arylsulfonium hexafluoroantitnonate salts,such as Cyracure UVI-6976, also both commercially from Dow Chemical.

The thermal curing does not generally have special features as to itsmethod but, instead, takes place in accordance with the customary andknown methods, such as heating in a convection oven or irradiation withIR lamps. A peroxide or azo initiator may be added.

In certain preferred embodiments, the primer and ink are cured withactinic radiation. Curing with actinic radiation is carried out usingcustomary and known radiation sources and optical auxiliary measures.Non-limiting examples of suitable radiation sources includehigh-pressure or low-pressure mercury vapor lamps, with or withoutdoping, or electron beam sources. Their arrangement is known inprinciple and can be adapted to the circumstances of the work piece,i.e. the substrate to be printed, and the process parameters.

Curing can take place in stages, i.e. by multiple exposures to light oractinic radiation. It can also take place by alternate exposures to UVradiation and electron beams. Where thermal curing and curing withactinic radiation are employed together, these methods can be usedsimultaneously or in alternation. Where the two curing methods are usedalternatively, it is possible, for example, to commence with the thermalcuring and to end with the curing with actinic radiation, or vice versa.

Various post processing steps can be performed on the printed substrate.For example, it may be desirable to coat the cured substrate with aprotective varnish topcoat. Suitable varnishes and protective top coatsare known in the art and can be selected based on the type of substrateand the desired end finish of the product. In various embodiments, theprotective top coat can be of the same formulation as the primer layer.

EXAMPLES Example 1 Ink Formulation

Ink formulations useful herein are made having the composition shown inTable 1 below. Specific materials are exemplary of classes of materialshaving similar functional characteristics within the composition.

TABLE 1 Ink Formulation Material name Percentage by weight Propoxylatedneopentyl glycoldiacrylate 10 to 60% SR9003 (Sartomer Company, Inc.)Isobornyl Acrylate(Sartomer Company, Inc.) 20 to 55% CD 420 (SartomerCompany, Inc.)  0 to 20% Photoinitiator  2 to 20% Pigment Base  2 to 30%

The ink formulations are highly compatible with the ICIMAR™ MD UV 2020RScoater varnish, sold by ICI Packaging Coatings Ltd. of Sutton Fields,England. The combination of the ink formulation and the 2020RS coatervarnish provides improved printing quality on metal substrates.

Example 2 Black Ink Formulation

In various embodiments, black ink formulations are made within thecompositional ranges, including formulations that, for example, havespecific mid-point levels for each individual component, andcombinations thereof, as shown in Table 2 below.

TABLE 2 Black Ink Formulation Material name Percentage by weightPropoxylated neopentyl glycol diacrylate 15 to 20% SR9003 (SartomerCompany, Inc.) Isobornyl 45 to 55% Acrylate (Sartomer Company, Inc.) CD420 (Sartomer Company, Inc.)  8 to 15% Photoinitiator (Genocure L ™ byRahn USA  2 to 10% of Aurora, Illinois) Photoinitiator (Esacure One byLamberti Sp.  2 to 10% A. of Gallarate, Italy) Black Base  5 to 10%

The black ink formulation has a surface tension of 30.6 dynes/cm2. Theblack ink formulation has a viscosity of 12.5 centipoises at 25° C. anda viscosity of 6.49 centipoises at 45° C.

The black ink formulation is highly compatible with the ICIMAR™ MD UV2020RS coater varnish sold by ICI Packaging Coatings Ltd. of SuttonFields, England. The combination of the black ink formulation and the2020RS coater varnish provides improved printing quality on metalsubstrates.

Example 3 Cyan Ink Formulation

Similarly, inkjet formulations are made within the compositional rangesshown in Table 3, below.

TABLE 3 Cyan Ink Formulation Material Name Percentage by weightPropoxylated neopentyl glycol diacrylate 30 to 40% SR9003 (SartomerCompany, Inc.) Isobornyl 45 to 55% Acrylate (Sartomer Company, Inc.)Photoinitiator (Genocure LTM by Rahn USA of  2 to 10% Aurora, Illinois)Photoinitiator (Esacure TZT by Lamberti Sp. A. of  2 to 10% Gallarate,Italy) Cyan Base  5 to 10%

The cyan ink formulation has a surface tension of 31 dynes/cm2. The cyanink formulation has a viscosity of 10.8 centipoises at 25° C. and aviscosity of 5.65 centipoises at 45° C.

The cyan ink formulation is highly compatible with the ICIMAR™ MD UV2020RS coater varnish, sold by ICI Packaging Coatings Ltd. of SuttonFields, England. The combination of the cyan ink formulation and the2020RS coater varnish provides improved printing quality on metalsubstrates.

Example 4 Magenta Ink Formula

Similarly, inkjet ink formulations are made within the compositionalranges show in Table 4 below.

TABLE 4 Magenta Ink Formula Material Name Percentage by WeightPropoxylated neopentyl glycol diacrylate 15 to 30% SR9003 (SartomerCompany, Inc.) Isobornyl 45 to 55% Acrylate (Sartomer Company, Inc.)Photoinitiator (Genocure LTM by Rahn USA of  2 to 10% Aurora, Illinois)Photoinitiator (Esacure TZT by Lamberti Sp. A. of  2 to 10% Gallarate,Italy) Magenta Base 12 to 25%

The magenta ink formulation has a surface tension of 30.9 dynes/cm2. Themagenta ink formulation has a viscosity of 15.4 centipoises at 25° C.and a viscosity of 8.14 centipoises at 45° C.

The magenta ink formulation is highly compatible with the ICIMAR™ MD UV2020RS coater varnish, sold by ICI Packaging Coatings Ltd. of SuttonFields, England. The combination of the magenta ink formulation and the2020RS coater varnish provides improved printing quality on metalsubstrates.

Example 5 Yellow Ink Formula

Similarly, inkjet ink formulations are made within the compositionalranges shown in Table 5 below.

TABLE 5 Yellow Ink Formula Material Name Percentage by Weight IsobornylAcrylate (Sartomer Company, Inc.) 40 to 50% Propoxylated neopentylglycol diacrylate  8 to 20% SR9003 (Sartomer Company, Inc.) CD 420  5 to15% (Sartomer Company, Inc.) Photoinitiator (Genocure LTM by Rahn USA of 2 to 10% Aurora, Illinois) Photoinitiator (Esacure TZT by Lamberti Sp.A. of  2 to 10% Gallarate, Italy) Transparent Yellow Base 10 to 25%

The yellow ink formulation has a surface tension of 30.5 dynes/cm2. Theyellow ink formulation has a viscosity of 12.1 centipoises at 25° C. anda viscosity of 6.57 centipoises at 45° C.

The yellow ink formulation is highly compatible with the ICIMAR™ MD UV2020RS coater varnish, sold by ICI Packaging Coatings Ltd. of SuttonFields, England. The combination of the yellow ink formulation and the2020RS coater varnish provides improved printing quality on metalsubstrates.

Although the invention is described herein with reference to thepreferred embodiment, one skilled in the art will readily appreciatethat other applications may be substituted for those set forth hereinwithout departing from the spirit and scope of the present invention.Accordingly, the invention should only be limited by the Claims includedbelow.

The invention claimed is:
 1. A method of ink jet printing onto ametallic substrate, comprising the steps of: applying a primer having aprimer viscosity of from about 100 to about 300 centipoises onto themetallic substrate, wherein the primer has a surface energy of fromabout 20 to about 50 milliNewtons per meter; ink jet printing an inkhaving an ink viscosity greater than the viscosity of the primer overthe primer while the primer is wet; wherein the primer has a film weightof about 2 to about 6 g/m² of an ink film as formed by the primer andthe ink jet ink; and simultaneously curing the primer and the ink jetink on the substrate.
 2. The method of claim 1, wherein the primer has asurface energy of about 20 to about 25 milliNewtons per meter.
 3. Themethod of claim 1, further comprising the step of: applying the primerat a temperature of from about 20 degree C. to about 40 degree C.
 4. Themethod of claim 1, wherein the metallic substrate is selected from thegroup consisting of metals, metal alloys, and metal-containingsubstrates.
 5. The method of claim 1, wherein the metallic substratecomprises a sheet metal.
 6. The method of claim 1, further comprisingthe step of: applying an overcoat to the primer and ink jet on the sheetmetal.
 7. The method of claim 1, wherein the overcoat and the primer areof the same chemical formulation.
 8. The method of claim 7, furthercomprising the step of: shaping the printed sheet metal into a formedproduct.
 9. The method of claim 1, wherein the primer and the ink jetink are actinic radiation curable; and further comprising the step ofcuring the primer and the ink jet ink with actinic radiation.